Rotate Image

 1 #include <iostream>
 2 #include <vector>
 3 using namespace std;
 4 
 5 class Solution {
 6 public:
 7     void rotate(vector< vector<int> > &matrix)
 8     {
 9         if (matrix.size() == 0) {
10             return;
11         }
12         int row = matrix.size();
13         int col = matrix[0].size();
14 
15         if (row != col) {
16             return;
17         }
18         // 先按行换
19         for (int i = 0; i < row / 2; ++i) {
20             for (int j = 0; j < col; ++j)
21             swap(matrix[i][j], matrix[row - i - 1][j]);
22         }
23         // 再按主对角线换
24         for (int i = 0; i < row; ++i) {
25             for (int j = 0; j < col; ++j) {
26                 if (i > j) {
27                     swap(matrix[i][j], matrix[j][i]);
28                 }
29             }
30         }
31     }
32 
33 private:
34     void swap(int &lhs, int &rhs)
35     {
36         int temp = lhs;
37         lhs = rhs;
38         rhs = temp;
39     }
40 };
41 
42 int main(void)
43 {
44     Solution sl;
45 
46     int n = 1;
47     cout << "Enter the matrix‘s dem:";
48     cin >> n;
49 
50     vector< vector<int> >matrix(n, vector<int>(n));
51     for (int i = 0; i < n; ++i) {
52         for (int j = 0; j < n; ++j) {
53             matrix[i][j] = i * n + j + 1;
54         }
55     }
56 
57     cout << "Before:" << endl;
58     for (int i = 0; i < n; ++i) {
59         for (int j = 0; j < n; ++j) {
60             cout << matrix[i][j] << " ";
61         }
62         cout << endl;
63     }
64     sl.rotate(matrix);
65 
66     cout << "After:" << endl;
67     for (int i = 0; i < n; ++i) {
68         for (int j = 0; j < n; ++j) {
69             cout << matrix[i][j] << " ";
70         }
71         cout << endl;
72     }
73 
74     return 0;
75 }